Eddy-current signal analysis and inversion for semielliptical surface cracks

A scalar potential formulation of the Z formula for the change in impedance of an eddy-current probe caused by a surface-breaking flaw is developed. The resulting formula is evaluated using a finite-difference method, which permits calculation of Z for semielliptical flaws. The numerical results are checked by comparing calculations for rectangular-shaped flaws to previous calculations using an analytical solution for this geometry. Theoretical results are then verified by comparison with measurements on semielliptical fatigue cracks and EDM notches in aluminum alloy specimens using air-core eddy-current probes. An inversion method that compares features of the flaw profile, obtained by scanning the eddy-current probe along the length of the flaw, to a theoretical inversion chart (McFetridge chart) is demonstrated using the experimental data.     

The Pediatric Radiofrequency Ablation Registry's experience with Ebstein's anomaly. Pediatric Electrophysiology Society

INTRODUCTION: Abnormal anatomy and complex electrophysiology in patients with Ebstein's anomaly of the tricuspid valve may confound attempts at radiofrequency ablation (RFA). METHODS AND RESULTS: Data for 65 pediatric Ebstein's patients (9.8+/-5.4 years, 4 months to 20 years; 39+/-25 kg, 5.1 to 108 kg) were obtained from the Pediatric Radiofrequency Ablation Registry. The degree of tricuspid regurgitation (DOTR) and the degree of Ebstein's anomaly were assessed with echocardiography/Doppler. Leading indications were drug refractoriness (24 [37%] of 65 patients) and life-threatening arrhythmia (14 [22%] of 65 patients). For the 65 patients, 82 typical (nondecremental) accessory pathways (APs) (62% right free wall, 34% right septal, and 4% left sided), 17 other supraventricular tachycardias (1 ectopic atrial, 7 AV reentry, 5 Mahaim, and 4 intra-atrial reentry tachycardias), and 1 ventricular mechanism were mapped. Thirty-four (52%) of 65 patients had a single AP (21 right free wall, 10 septal, and 3 left); 19 (29%) of 65 patients multiple APs; 6 (9%) of 65 patients a single AP plus a non-AP mechanism; and 6 (9%) of 65 patients non-AP mechanism(s) only. RFA acute success rates and recurrence rates for right free wall, right septal, and other mechanisms were 79%/32%, 89%/29%, and 75%/27%. Mild DOTR and a body surface area (BSA) < or = 1.7 m2 independently predicted a better acute success rate. BSA < or = 1.7 m2 also predicted long-term success. CONCLUSION: In this patient subset, life-threatening arrhythmias and multiple electrophysiologic mechanisms are commonly encountered during RFA. Mild DOTR and a BSA < or = 1.7 m2 predict a higher acute success rate. While acute success rates are relatively high, recurrence is frequent.     

A Highly Potent and Selective Caspase 1 Inhibitor that Utilizes a Key 3‐Cyanopropanoic Acid Moiety

Herein, we examine the potential of a nitrile‐containing propionic acid moiety as an electrophile for covalent attack by the active‐site cysteine residue of caspase 1. The syntheses of several cyanopropanate‐containing small molecules based on the optimized peptidic scaffold of prodrug VX‐765 were accomplished. These compounds were found to be potent inhibitors of caspase 1 (IC₅₀ values ≤1 nM ). Examination of these novel small molecules against a caspase panel demonstrated an impressive degree of selectivity for caspase 1 inhibition over other caspase isozymes. Assessment of hydrolytic stability and selected ADME properties highlighted these agents as potentially useful tools for studying caspase 1 down‐regulation in various settings, including in vivo analyses.     

Is alexithymia related to psychosomatic disorder and somatizing?

The purpose of this study was to examine the relationship among alexithymia (as measured by the Toronto Alexithymia Scale--TAS and the scored version of the Archetypal 9 Test--SAT9), the presence or absence of classical psychosomatic disease, and the experience and expression of physical signs and symptoms. Subjects included thirty-two physical signs and symptoms. Subjects included thirty-two in-patients on a psychosomatic medicine unit (somatizing group), thirty-one out-patients who presented to a psychology clinic (psychiatric group), and thirty-four dental patients (comparison group). All subjects completed the TAS, the SAT9, the Hypochondriasis scale of the Minnesota Multiphasic Personality Inventory (MMPI Hs), the Physical Malfunctioning subscale of the MMPI (MMPI Physm), the Somatic Complaints subscale of the MMPI (MMPI Somc), the Hypochondriasis and Denial scales of the Basic Personality Inventory (BPI Hs and BPI Dn), and a demographic questionnaire. Age was significantly correlated with some of the TAS subscales (p < 0.001). There was no significant differences in SAT9 or TAS scores among the three subject groups (SAT9 F(2, 87) = 1.88, p = 0.16; TAS F(2, 92) = 2.91, p = 0.06). MMPI Hs, MMPI Physm, MMPI Somc, BPI Hs could significantly predict TAS (R = 0.46, F(4, 89) = 6.06, p = 0.0002) but not SAT9 scores (R = 0.26, F(5, 84) = 1.54, p = 0.20). Neither TAS (F(2, 92) = 2.13, p = 0.12) or SAT9 (F(2, 87) = 0.095, p = 0.91) scores differed significantly between subjects grouped according to whether they had none, one, or two or more classical psychosomatic disorders.(ABSTRACT TRUNCATED AT 250 WORDS)     

Leisure, public space and quality of life in the urban environment

The regeneraton of cities has focussed on changing the physical shape of the urban leisure environment in order to increase economic values at the expense of social values. An increased focus on the social outcomes of leisure spaces is needed if quality of life is to be improved for residents.     

Silicon sensors as process monitoring devices

Piezoresistive silicon based process monitoring devices (PMDs) employing flexible circuitry and substrates have been developed which are compatible with standard VLSI fabrication processes. These solid state sensors offer cost effective batch fabrication and a high degree of uniformity to produce either single elements or flexible conformable arrays. This is a state of the art report on emerging technology.     

500 GHz GaAs MMIC sampling wafer probe

A 500 GHz bandwidth GaAs MMIC sampling wafer probe is reported which incorporates a mechanical flexure and a micromachined GaAs IC for time domain on-wafer measurements. The GaAs IC incorporates a novel high speed pulse sharpener and a two-diode sampling bridge with a micromachined GaAs tip.<>     

Horizontal shear surface waves on corrugated surfaces

Experiments have been performed on horizontal shear surface-wave propagation along a corrugated surface. The results are in agreement with approximate theories used in analogous electromagnetic problems.     

Characterization of capacitive array for NDE applications

We have developed a capacitive array sensor which responds to the complex dielectric constant of an interrogated material. The sensor requires only single-sided access and operates in a differential mode for detection of discontinuities in the relative dielectric constant, _r , or in the absolute mode where the interest is in absolute quantities. The device in general is noncontacting but can be fabricated as an embedded sensor.Various proof-of-concept studies have been performed to explore possible applications of the device. In the differential mode, small surface features (notches) were detected in a conductor; in dielectrics, both surface and subsurface features were detected. The probe was sensitive to change in impedance caused by a curing epoxy, viewed through a graphite-epoxy composite panel.A study was performed to assess the use of the probe for noncontact characterization of sintering of ceramics. In this (absolute) mode, the effects of liftoff and dielectric constant must be separated. We propose a scheme based on the ability to multiplex the capacitive array probe to accomplish this. Preliminary investigation shows that the effect of parasitic capacitance between the probe and ground points in the environment must be suppressed.Contribution of the National Institute of Standards and Technology (formerly National Bureau of Standards); not subject to copyright.